Partially rotated eccentric drive for valve pin

ABSTRACT

An injection molding apparatus ( 5 ) comprising an injection molding machine (IMM), a heated manifold ( 60 ) that receives injection fluid ( 9 ) and distributes the injection fluid through a fluid distribution channel ( 120 ), a mold ( 70 ) having a cavity ( 80 ) and one or more valves ( 50 ) having a valve pin ( 100 ) the one or more valves ( 50 ) being comprised of:
         an electrically driven actuator ( 200 ),   a controller including an algorithm that controllably limits rotation of a shaft ( 12 ) or output rotation device ( 16, 430, 500 ) during the course of an entire injection cycle to selectable angular positions that create a moment arm that extends between selected a selected minimum moment arm and a selected maximum moment arm, the selectable angular positions being between 70 degrees above and 70 degrees below an angular position that corresponds to the selected maximum moment arm.

RELATED APPLICATIONS

This application is a continuation of PCT/US2019/046139 filed Aug. 12,2019 which in turn claims the benefit of priority to U.S. provisionalapplication Ser. No. 62/853,414 filed May 28, 2019 the disclosure ofwhich is incorporated by reference as if fully set forth herein.

This application is also a continuation of and claims the benefit ofpriority to U.S. application Ser. No. 15/811,877 filed Nov. 14, 2017which is a continuation of PCT/US2017/059641 filed Nov. 2, 2017 which inturn claims the benefit of priority to U.S. provisional application Ser.No. 62/421,696 filed Nov. 14, 2016, and U.S. Ser. No. 15/811,877 is alsoa continuation in part of U.S. application Ser. No. 15/204,555 filedJul. 7, 2016 which in turn is a continuation of PCT/US2016/016944 filedFeb. 8, 2016 which claims the benefit of priority to U.S. provisionalapplication 62/135,871 filed Mar. 20, 2015, the disclosures of which areincorporated by reference in their entirety as if fully set forthherein.

The disclosures of all of the following are incorporated by reference intheir entirety as if fully set forth herein: U.S. Pat. Nos. 5,894,025,6,062,840, 6,294,122 (7018), U.S. Pat. Nos. 6,309,208, 6,287,107,6,343,921, 6,343,922, 6,254,377, 6,261,075, 6,361,300 (7006), U.S. Pat.Nos. 6,419,870, 6,464,909 (7031), U.S. Pat. No. 6,062,840 (7052), U.S.Pat. No. 6,261,075 (7052US1), U.S. Pat. Nos. 6,599,116, 7,234,929(7075US1), U.S. Pat. No. 7,419,625 (7075US2), U.S. Pat. No. 7,569,169(7075US3), U.S. Pat. No. 8,297,836 (7087) U.S. patent application Ser.No. 10/214,118, filed Aug. 8, 2002 (7006), U.S. Pat. No. 7,029,268(7077US1), U.S. Pat. No. 7,270,537 (7077US2), U.S. Pat. No. 7,597,828(7077US3), U.S. patent application Ser. No. 09/699,856 filed Oct. 30,2000 (7056), U.S. patent application Ser. No. 10/269,927 filed Oct. 11,2002 (7031), U.S. application Ser. No. 09/503,832 filed Feb. 15, 2000(7053), U.S. application Ser. No. 09/656,846 filed Sep. 7, 2000 (7060),U.S. application Ser. No. 10/006,504 filed Dec. 3, 2001, (7068),International Application WO2011119791 filed Mar. 24, 2011 (7094), U.S.application Ser. No. 10/101,278 filed Mar. 19, 2002 (7070) and PCTApplication No. PCT/US11/062099 (7100WO0) and PCT Application No.PCT/US11/062096 (7100WO1), U.S. Pat. Nos. 8,562,336, 8,091,202 (7097US1)and U.S. Pat. No. 8,282,388 (7097US2), U.S. Pat. No. 9,205,587(7117US0), U.S. application Ser. No. 15/432,175 (7117US2) filed Feb. 14,2017, U.S. Pat. No. 9,144,929 (7118US0), U.S. Publication No.20170341283 (7118US3), U.S. Pat. No. 9,724,861 (7129US4), U.S. Pat. No.9,662,820 (7129US3), international application WO2014172100 (7131WO0),Publication No. WO2014209857 (7134WO0), international applicationWO2015066004 (7140WO0), Publication No. WO2015006261 (7135WO0),International application Publication No. WO2016153632 (7149WO2),International application publication no. WO2016153704 (7149WO4), U.S.Pat. No. 9,937,648 (7135US2), U.S. Pat. No. 10,569,458 (7162US1),International Application WO2017214387 (7163WO0), InternationalApplication PCT/US17/043029 (7165WO0) filed Jul. 20, 2017, InternationalApplication PCT/US17/043100 (7165WO1), filed Jul. 20, 2017 andInternational Application PCT/US17/036542 (7163WO0) filed Jun. 8, 2017and International Application WO2018129015 (7169WO0), Internationalapplication WO2018148407 (7170WO0), International applicationWO2018148407 (7171WO0), international application WO2018175362(7172WO0), international application WO2018194961 (7174WO0),international application WO2018200660 (7176WO0), internationalapplication WO2019013868 (7177WO0), international applicationWO2019100085 (7178WO0), international application WO2020176479(7185WO0), international application WO2021/034793 (7187WO0),international application WO2021080767 (7188WO0).

BACKGROUND OF THE INVENTION

Actuators that use a driven rotating mechanism such as the rotor of anelectric motor to effect the linear drive of a valve pin have been usedin injection molding systems such as disclosed in U.S. Pat. No.6,294,122, the disclosure of which is incorporated by reference as iffully set forth herein.

One approach to using an eccentric cam to drive a valve pin in aninjection molding system is to construct the device so that the cam canrotate though an entire 360 degrees (referred to herein as full rotationdevice or “FRD”). On some devices, this is inevitable as there is nopractical way to limit the amount of rotation as the action of the camis continuous such that the cam does not come to rest so it is necessaryto continue its operation as it enters the 361^(st) degree of rotation.Overhead cams as found in automobile engines are an example.

Another approach is to use only a segment of the full 360 degrees ofrotation (hereinafter “PRD”). Instead of rotating continuously, thedriven shaft of the actuator that rotatably drives the eccentric berotated through a selected fraction of the 360 degrees and then stopped.When the shaft direction is reversed, the sled to which the valve pin isinterconnected can be drivably moved in the opposite direction.

Preferably, the rotating shaft or rotor of the actuator, typically anelectric actuator, is interconnected to a rotational speed reducer isrequired as motor output speeds are too high and of too low a torque tobe useful. Preferably a strain wave gear is used as the rotational speedreducer.

SUMMARY OF THE INVENTION

With a PRD based system:

1) The end-of-stroke positions of a valve pin can be established by anelectronic controller (1000) instead of manually or by trial and erroras with an FRD based system. With a PRD system, the valve pin, beinginterconnected to a linearly moving sled, slide or pin mount, can be setto a selectable end of stroke position along the linear path of travelof the valve pin by controllably rotating the cam a selected degree ofrotation around the axis of rotation (12 a, R3 a) with a programmableservo motor. The end of stroke or starting position of the valve pin,then, is controllably selectable via an electric or electronic controlsystem. In an FRD system, the end of stroke or start cycle pin positionis established only mechanically by varying the mounting location of theactuator assembly with respect to the hot runner and the gate to themold. Thus, in a PRD system, establishing the starting or end of strokevalve pin position is simpler for the user and can be easily altered toaccommodate wear and other changes to the system.

2) The travel path or length of an injection cycle stroke of a valve pincan be modified for the same reasons as stated above regarding theability to pre-select the end of stroke or starting positions of thevalve pin. Thus, it is possible to meter the amount of polymer enteringthe gate whereas a pin close to the gate restricts the flow relative toa pin further away.

3) In an FRD system that uses a sled, slide or pin mount such sled 43shown in FIGS. 6-9 , the location of the force F as applied by the outersurface of the cam member 600 on the sled 43 moves across a surface thatis as long as the full stroke of the actuator, a geometric function ofhaving a fully rotated cam or eccentrically driven pin. However theopposing force against the linear travel of the pin 100 from forceexerted by the fluid material on the pin does not move; it remains fixedalong the axis of the pin 100 and gate. This creates a “couple”, a pairof forces F that are not co-axial as shown in FIG. 6A which creates atendency for the sled 43 to want to rotate. The amount of thiscounteraction depends linearly on the force F and the distance, D, FIG.6A. A PRD that only rotates the eccentrically mounted cam member 600 aportion of the full 360 degrees during the course of an injection cyclethus reduces the distance, D which reduces the degree of strength neededto maintain the sled's 43 rotational position.

4) The same is true regarding the amount of the force. The more force F,the more need there is to counter the tendency of the sled 43 to rotate.When using the FRD, the amount of force that is exerted on the pinvaries enormously over the entire 360 degree rotation of the cam member600. When the cam 600 is located mid-stroke on either design, FIG. 6B,the force on the valve pin 100 is calculated as the torque at the shaftmultiplied by the moment arm, M. The radius, R, is also equal to halfthe stroke for the FRD. But as the cam 600 moves the sled 43 to the endof stroke condition, the moment arm also changes, becoming shorter. Onthe FRD, it eventually becomes zero. The force, then, is again equal tothe moment arm times the torque, but because the arm is zero, the forceis a theoretical infinite. An advantage of the PRD where the change inthe length of the moment arm M is limited, FIG. 6B, and controlled. But,that's not to say that a very small amount of rotation is preferred. Anadditional amount of force during the pin-closed portion of the pin moveis helpful as semi-solidified polymer is in the gate and this takes anadded level of force to displace.

5) The opposite is true for the pin velocity. At mid-stroke, thevelocity is highest (for both FRD & PRD), but at the end-of-strokeconditions, the velocity of the pin become zero for the FRD. Thevelocity of the PRD must also be zero at the end of stroke because themotor must be stopped. However, when it is time to move the pin 100 fromthe end of stroke position again, the FRD system needs to start itsmotor again to create a rotational velocity and overcome the geometricconditions where the pin velocity is also zero due to a zero-lengthmoment arm resulting in slower pin acceleration. With the PRD, themoment arm at the endo of stroke is shorter than at mid-stroke, butinfinitely longer than zero as in the FRD thereby facilitating a higheracceleration of the pin beginning from the end of stroke position. Thisis helpful in getting the pin out of the way in molding operations.

6) While use of a PRD system keeps the moment arm M at the pin opencondition about equal to the pin closed position, that equality can bechanged to bias the moment arm at one end compared to the other to suitcustomer preferences.

A preferred range of partial rotation for a PRD system between fullyopen and fully closed (or end of stroke) position is about 80 degrees orabout 40 degrees above and about 40 degrees below the full or maximummoment arm rotational position of the cam 600 which is typically the 90degree or 270 degree position to which the cam 600 has been rotated,although other degrees of partial rotation less than a full 360 degreescan be used to achieve the results of a PRD system as described above.

In accordance with the invention there is provided an injection moldingapparatus (5) comprising:

an injection molding machine (IMM), a heated manifold (60) that receivesinjection fluid (9) from the injection molding machine and distributesthe injection fluid through a fluid distribution channel (120), a mold(70) having a cavity (80) and one or more valves (50) having a valve pin(100) that controls injection of the injection fluid (9) into the moldcavity, the one or more valves (50) being comprised of: an electricallydriven actuator (200) having a driven rotatable rotor drivably rotatablyinterconnected to a shaft (12) or to an output rotation device (16, 430,500) that is rotatably drivable 360 degrees around an output rotationaxis (12 a, R3 a),

a rotary to linear converter device that includes an eccentric (600)that is eccentrically disposed or mounted off center a selected distance(ED, R) from the output rotation axis (12 a, R3 a) in an arrangementsuch that when the shaft (12) or rotation device (16, 430, 500) isrotatably driven, the eccentric (600) is eccentrically rotatablydrivable around the output rotation axis (12 a, R3 a) to selectableangular positions above and below either a 270 degree position or a 90degree position,

a controller (1000) interconnected to the shaft (12) or output rotationdevice (16, 430, 500), the controller (1000) including an algorithm thatcontrollably limits rotation of the shaft (12) or output rotation device(16, 430, 500) during the course of an entire injection cycle to angularpositions between about 70 degrees above and 70 degrees below the 270degree position or between about 70 degrees above and 70 degrees belowthe 90 degree position,

wherein a preselected angular position between the 270 or 90 degreeposition and 70 degrees above defines a fully open valve pin position(PFO) and a preselected angular position between the 270 or 90 degreeposition and 70 degrees below defines a valve pin position where thegate is closed (PFC),

the pin or shaft (100) being interconnected to or interengaged with thedriven eccentric (600) in an arrangement such that the pin or shaft(100) is driven reciprocally along a linear path of travel (A) as theeccentric (600) is eccentrically rotatably driven.

In such an apparatus the eccentric can comprise a cam member (600), therotary to linear converter device including a slide or sled (43)interconnected to the drive shaft or rotor (12), the slide or sled (43)having a cammed slot (43 sl) having a slot surface (43 ss) adapted toengage an exterior surface (600 cs) of the eccentric (600) to cause thesled or slide (43) to move along the linear path of travel (A) as theeccentric (600) is eccentrically rotatably driven around the outputrotation axis (12 a, R3 a).

The rotary to linear converter device can be adapted to mechanically orfrictionally stop or limit linear travel of the valve pin (100) at or toselectable linear positions.

The cam member (600), slide or sled 43 or associated mounts 40 can beadapted to exert a radial force (RF) between the slide or sled (43) anda complementary fixed surface (40 as) at selectable rotational orangular positions of the cam member (600), the radial force (RF) beingsufficient to stop rotational movement of the cam member (600) or tostop linear movement of the slide or sled (43).

Such an apparatus typically further includes a rotational speed reducingmechanism (46) interconnected to the drive shaft or rotor (12) of theactuator (200), the rotational speed reducing mechanism (46) beingcomprised of a rotatably driven generally elliptical or other noncircular shaped device (430, 472) or one or more rotatably driven gears(430, 700) interconnected to the drive shaft or rotor (12) in anarrangement such that rotation of the drive shaft or rotor (12) istransmitted to an output rotation device (16, 430, 500) to cause theoutput rotation device (16, 430, 500) to be rotatably driven at aselected lower rotational speed relative to a rotational speed of thedrive shaft or rotor (12).

The rotational speed reducing mechanism can comprise a strain wave gear.

the electrically driven actuator (200) is typically mounted in a remotelocation or position relative to the heated manifold (60) such that theelectrically driven actuator (200) is insulated or isolated from thermalcommunication with the heated manifold (60).

In such an apparatus an elongated shaft (20, 20 f) can drivablyinterconnect the rotatable output shaft (12) or the output rotationdevice (16, 430, 500) to a rotary to linear converter (40) that isinterconnected to the pin or shaft (100) to convert rotation of theoutput shaft (12) or the output rotation device (16, 430, 500) to linearmotion and drive the pin or shaft (100) linearly.

The elongated shaft typically has a length (CL) sufficient to mount theactuator (200) in a position or location remote from the heated manifold(60) such that the actuator (200) is isolated from substantial heatcommunication with the heated manifold (60) wherein the actuator remainsinterconnected to the valve pin (100) via the one or more elongatedcables (20, 20 f).

The elongated cable or shaft (20 f) can have a length (CL) and a cableaxis (CA) that is flexibly bendable along at least a portion of thecable axis (CA) into a curved or curvilinear configuration (CF)interconnects the rotatable output shaft (12) or the output rotationdevice (16, 430, 500) to a rotary to linear converter (40) that isinterconnected to the pin or shaft (100) to convert rotation of theoutput shaft (12) or the output rotation device (16, 430, 500) to linearmotion and drives the pin or shaft (100) linearly.

The algorithm preferably controllably limits rotation of the shaft (12)or output rotation device (16, 430, 500) during the course of an entireinjection cycle to angular positions between about 40 degrees above and40 degrees below the 270 degree position or between about 40 degreesabove and 40 degrees below the 90 degree position wherein a preselectedangular position between 40 degrees above the 270 or 90 degree positiondefines the fully open valve pin position (PFO) and a preselectedangular position 40 below the 270 or 90 degree position defines thevalve pin position where the gate is closed (PFC).

The valve pin (100) is typically maintained in engagement with theradial surface (600 cs) under a spring force (SF)

In another aspect of the invention there is provided a method ofinjecting a selected injection fluid (9) into a cavity (80) of a mold(70) in an injection molding apparatus (5) comprised of an injectionmolding machine (IMM), a heated manifold (60) that receives injectionfluid (9) from the injection molding machine and distributes theinjection fluid through a fluid distribution channel (120), a mold (70)having a cavity (80) and one or more valves (50) having a valve pin(100) that controls injection of the injection fluid (9) into the moldcavity, the method comprising: selecting an electrically driven actuator(200) having a driven rotatable rotor drivably rotatably interconnectedto an output shaft (12) or to an output rotation device (16, 430, 500)that is rotatably driven around an output rotation axis (12 a, R3 a),disposing or mounting a cam device or surface (600) eccentrically offcenter a selected distance (ED, R) from the output rotation axis (12 a,R3 a) in an arrangement such that when the shaft (12) or rotation device(16, 430, 500) is rotatably driven, the cam member or surface (600) iseccentrically rotatably driven around the output rotation axis (12 a, R3a), controllably rotating the shaft (12) or output rotation device (16,430, 500) during the course of an entire injection cycle to to angularpositions between about 70 degrees above and 70 degrees below the 270degree position or between about 70 degrees above and 70 degrees belowthe 90 degree position wherein a preselected angular position betweenthe 270 or 90 degree position and 70 degrees above defines a fully openvalve pin position (PFO) and a preselected angular position between the270 or 90 degree position and 70 degrees below defines a valve pinposition where the gate is closed (PFC), interconnecting to orinterengaging with the pin or shaft (100) the driven cam member (600) inan arrangement such that the pin or shaft (100) is drivable reciprocallyalong a linear path of travel (A) as the cam member (600) iseccentrically rotatably driven, controllably operating the electricallydriven actuator to drive the pin or shaft (100).

In another aspect of the invention there is provided an injectionmolding apparatus (5) comprising:

an injection molding machine (IMM), a heated manifold (60) that receivesinjection fluid (9) from the injection molding machine and distributesthe injection fluid through a fluid distribution channel (120), a mold(70) having a cavity (80) and one or more valves (50) having a valve pin(100) that controls injection of the injection fluid (9) into the moldcavity,

the one or more valves (50) being comprised of: an electrically drivenactuator (200) having a driven rotatable rotor drivably rotatablyinterconnected to a shaft (12) or to an output rotation device (16, 430,500) that is rotatably drivable 360 degrees around an output rotationaxis (12 a, R3 a),

a rotary to linear converter device that includes an eccentric (600)that is eccentrically disposed or mounted off center a selected distance(ED, R) from the output rotation axis (12 a, R3 a) in an arrangementsuch that when the shaft (12) or rotation device (16, 430, 500) isrotatably driven, the eccentric (600) is eccentrically rotatablydrivable around the output rotation axis (12 a, R3 a) to selectableangular positions above and below either a 270 degree position or a 90degree position,

a controller (1000) interconnected to the shaft (12) or output rotationdevice (16, 430, 500), the controller (1000) including an algorithm thatcontrollably limits rotation of the shaft (12) or output rotation device(16, 430, 500) during the course of an entire injection cycle toselectable angular positions that create a moment arm that extendsbetween a selected minimum moment arm relative to an absolute minimummoment arm (MM1 which is typically the 0 degree position and MM2 whichis typically the 180 degree position) and a selected maximum moment arm,the selectable angular positions being between 70 degrees above and 70degrees below an angular position that corresponds to the selectedmaximum moment arm (which is typically the 90 degree and 270 degreepositions),

wherein a preselected angular position between the angular position thatcorresponds to the selected maximum moment arm and 70 degrees abovedefines a fully open valve pin position (PFO) and a preselected angularposition between the angular position that corresponds to the selectedmaximum moment arm and 70 degrees below defines a valve pin positionwhere the gate is closed (PFC),

the pin or shaft (100) being interconnected to or interengaged with thedriven eccentric (600) in an arrangement such that the pin or shaft(100) is driven reciprocally along a linear path of travel (A) as theeccentric (600) is eccentrically rotatably driven.

In such an apparatus the selectable angular positions are preferablybetween 40 degrees above and 40 degrees below the angular position thatcorresponds to the selected maximum moment arm which is typically a 90or 270 degree position.

In such an apparatus, the first selected angular position is preferablydisposed between the angular position that corresponds to the maximummoment arm and 70 degrees above the angular position that corresponds tothe maximum moment arm defines a valve pin fully open position andwherein a second selected angular position disposed between the angularposition that corresponds to the maximum moment arm and 70 degrees belowthe angular position that corresponds to the maximum moment arm definesan end of stroke, valve pin closed or gate closed position.

In such an apparatus the first selected angular position is preferablydisposed between the angular position that corresponds to the maximummoment arm and 40 degrees above the angular position that corresponds tothe maximum moment arm defines a valve pin fully open position andwherein a second selected angular position disposed between the angularposition that corresponds to the maximum moment arm and 40 degrees belowthe angular position that corresponds to the maximum moment arm definesan end of stroke, valve pin closed or gate closed position.

In such an apparatus the eccentric can comprise a cam member (600), therotary to linear converter device including a slide or sled (43)interconnected to the drive shaft or rotor (12), the slide or sled (43)having a cammed slot (43 sl) having a slot surface (43 ss) adapted toengage an exterior surface (600 cs) of the eccentric (600) to cause thesled or slide (43) to move along the linear path of travel (A) as theeccentric (600) is eccentrically rotatably driven around the outputrotation axis (12 a, R3 a).

The rotary to linear converter device can be adapted to mechanically orfrictionally stop or limit linear travel of the valve pin (100) at or toselectable linear positions.

The cam member (600), slide or sled 43 or associated mounts 40 can beadapted to exert a radial force (RF) between the slide or sled (43) anda complementary fixed surface (40 as) at selectable rotational orangular positions of the cam member (600), the radial force (RF) beingsufficient to stop rotational movement of the cam member (600) or tostop linear movement of the slide or sled (43).

Such an apparatus can further include a rotational speed reducingmechanism (46) interconnected to the drive shaft or rotor (12) of theactuator (200), the rotational speed reducing mechanism (46) beingcomprised of a rotatably driven generally elliptical or other noncircular shaped device (430, 472) or one or more rotatably driven gears(430, 700) interconnected to the drive shaft or rotor (12) in anarrangement such that rotation of the drive shaft or rotor (12) istransmitted to an output rotation device (16, 430, 500) to cause theoutput rotation device (16, 430, 500) to be rotatably driven at aselected lower rotational speed relative to a rotational speed of thedrive shaft or rotor (12).

In such an apparatus, the rotational speed reducing mechanism cancomprise a strain wave gear.

In such an apparatus the electrically driven actuator (200) can bemounted in a remote location or position relative to the heated manifold(60) such that the electrically driven actuator (200) is insulated orisolated from thermal communication with the heated manifold (60).

In such an apparatus, an elongated shaft (20, 20 f) can be drivablyinterconnected to the rotatable output shaft (12) or the output rotationdevice (16, 430, 500) to a rotary to linear converter (40) that isinterconnected to the pin or shaft (100) to convert rotation of theoutput shaft (12) or the output rotation device (16, 430, 500) to linearmotion and drive the pin or shaft (100) linearly.

In such an apparatus, the elongated shaft can have a length (CL)sufficient to mount the actuator (200) in a position or location remotefrom the heated manifold (60) such that the actuator (200) is isolatedfrom substantial heat communication with the heated manifold (60)wherein the actuator remains interconnected to the valve pin (100) viathe one or more elongated cables (20, 20 f).

In such an apparatus an elongated cable or shaft (20 f) having a length(CL) and a cable axis (CA) that is flexibly bendable along at least aportion of the cable axis (CA) into a curved or curvilinearconfiguration (CF) can interconnect the rotatable output shaft (12) orthe output rotation device (16, 430, 500) to a rotary to linearconverter (40) that is interconnected to the pin or shaft (100) toconvert rotation of the output shaft (12) or the output rotation device(16, 430, 500) to linear motion and drives the pin or shaft (100)linearly.

In such an apparatus, the cam member (600) can comprise a disk, wheel,pin or projection (600 p) projecting axially from a rotatable member(500) that is controllably rotatable around a rotation axis (R3 a) orcomprises a radial surface (600 cs) of a rotatable member (500)controllably rotatable around a rotation axis (R3 a).

In such an apparatus, the valve pin (100) is typically maintained inengagement with the radial surface (600 cs) under a spring force (SF).

In another aspect of the invention there is provided a method ofinjecting a selected injection fluid (9) into a cavity (80) of a mold(70) in an injection molding apparatus (5) comprised of an injectionmolding machine (IMM), a heated manifold (60) that receives injectionfluid (9) from the injection molding machine and distributes theinjection fluid through a fluid distribution channel (120), a mold (70)having a cavity (80) and one or more valves (50) having a valve pin(100) that controls injection of the injection fluid (9) into the moldcavity, the method comprising:

selecting an electrically driven actuator (200) having a drivenrotatable rotor drivably rotatably interconnected to an output shaft(12) or to an output rotation device (16, 430, 500) that is rotatablydriven around an output rotation axis (12 a, R3 a),

disposing or mounting an eccentric (600) eccentrically off center aselected distance (ED, R) from the output rotation axis (12 a, R3 a) inan arrangement such that when the shaft (12) or rotation device (16,430, 500) is rotatably driven, the eccentric (600) is eccentricallyrotatably driven around the output rotation axis (12 a, R3 a),

controllably rotating the shaft (12) or output rotation device (16, 430,500) during the course of an entire injection cycle to selectableangular positions that create a moment arm that extends between selecteda selected minimum moment arm and a selected maximum moment arm, theselectable angular positions being between 70 degrees above and 70degrees below an angular position that corresponds to the selectedmaximum moment arm,

wherein a preselected angular position between the angular position thatcorresponds to the selected maximum moment arm and 70 degrees abovedefines a fully open valve pin position (PFO) and a preselected angularposition between the angular position that corresponds to the selectedmaximum moment arm and 70 degrees below defines a valve pin positionwhere the gate is closed (PFC),

interconnecting to or interengaging with the pin or shaft (100) thedriven cam member (600) in an arrangement such that the pin or shaft(100) is drivable reciprocally along a linear path of travel (A) as theeccentric (600) is eccentrically rotatably driven,

controllably operating the electrically driven actuator to drive the pinor shaft (100) or shaft (100).

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages of the invention may be betterunderstood by referring to the following description in conjunction withthe accompanying drawings in which:

FIG. 1 is a sectional schematic view of an injection molding apparatusaccording to the invention showing a pair of remotely mounted electricactuators each separately interconnected via a rigid drive shaft to arotational valve pin speed reducer, torque increaser device which inturn is drivably interconnected via an eccentric device to a linearlydriven valve pin.

FIG. 2 is an enlarged sectional view of a portion of the FIG. 1apparatus showing an electric actuator having a rotational speed reducermounted to a top clamp plate and showing an interconnection of the rotorof the motor and speed reducer to a rotary to linear movement convertermechanism that is in turn interconnected to a valve pin.

FIG. 3 is a top perspective view of a subassembly of an electric motoractuator interconnected via an elongated rigid shaft to a rotationalspeed reducer and rotary to linear movement converter as in FIG. 2 .

FIG. 4 is a view similar to FIG. 3 showing the actuator interconnectedto the speed reducer via an elongated flexible shaft.

FIG. 5 is a top perspective exploded view of an electric actuator whosedriven shaft is connected directly to a speed reducer which isinterconnected to a rotary to linear converter where the converter is inan downstream position.

FIGS. 5A, 5B, 5C are schematic sectional views of a rotationally drivenoutput device having a cammed surface interengaged with pin or shaftsuch that the pin or shaft is driven at variable linear speed oncomplete rotation of the of the rotationally driven output device.

FIG. 6 is a top left partially exploded perspective view of asubassembly of an electric actuator, a strain wave gear rotation speedreducer such as shown in FIGS. 10-12D and an eccentrically driven rotaryto linear drive sled converter.

FIG. 6A is a top right partially exploded view similar to FIG. 6 showingan alternative configuration of the eccentrically driven rotary tolinear sled components.

FIGS. 6B-6C are front views of the forward end rotating disk andassociated eccentrically mounted cam member, eccentrically driven rotaryto linear converter and the valve or drive pin of the FIGS. 5, 6, 6Asubassemblies showing the rotation disk and the eccentric cam member ina 270 degree maximum moment midstroke rotational position and forillustration purposes showing in dashed lines an embodiment where inFIG. 6B the maximum rotational valve pin fully upstream open angularposition is 70 degrees above or beyond 270 degree maximum momentposition (at 340 degrees), and in FIG. 6C showing a position of 70degrees before or below the maximum moment 270 degree midstroke position(at 200 degrees) at which position the valve pin closes the gate or in aclosed gate position.

FIGS. 6D, 6E are front views similar to FIGS. 6B, 6C specificallyshowing an alternative embodiment where in FIG. 6D the maximumrotational valve pin fully upstream open angular position is 40 degreesabove or beyond 270 degree maximum moment position (at 310 degrees), andin FIG. 6E showing a position of 40 degrees before or below the maximummoment 270 degree midstroke position (at 230 degrees) at which positionthe valve pin closes the gate or in a closed gate position.

FIG. 6F is a top front perspective view of the forward end rotating diskand associated eccentrically mounted cam member, rotary to linearconverter and drive pin of the speed reducer of the FIGS. 5, 6subassembly showing the outer circumferential surface 600 cs of the cammember in an angular position that is adapted to cause the surface 600cs to engage and forcibly push against the travel member surface 43 hsswhich in turn causes the outer surface 43 s of travel member 43 toforcibly engage against a complementary surface 40 as of the supportwhich causes the slide, sled or travel member 43 to come to a hard stop.

FIGS. 7A, 7B, 7C are a series of front views of the forward end rotatingdisk and associated eccentrically mounted drive pin of the speed reducerelement of the FIGS. 5, 6 subassembly showing the rotation disk andeccentric pin in a series of successive rotational positions during thecourse of an injection cycle.

FIG. 8 is a view similar to FIG. 6 showing the forward mounting or drivedisk, eccentric drive pin and rotary to linear movement components inexploded relationship.

FIG. 9 is a front view of the FIG. 8 subassembly in assembled formshowing the relationship of the speed reducing device to the forwardmounting or drive disk when assembled.

FIG. 10 is side sectional view of the FIG. 8 subassembly in assembledform.

FIG. 11 is a top left perspective exploded view of the pin speedreducing, torque increasing or modifying device of the FIG. 10 device.

FIG. 12A is a front view of the speed reducing device assembly showingthe thin walled rotatable bearing component mounted within theflexspline component mounted within the circular spline component withthe bearing and flexspline components disposed in an initial 0 degreeposition.

FIG. 12B is a view similar to FIG. 12A showing the bearing andflexspline components disposed in a subsequent 45 degree position.

FIG. 12C is a view similar to FIG. 12A showing the bearing andflexspline components disposed in a subsequent 180 degree position.

FIG. 12D is a view similar to FIG. 12A showing the bearing andflexspline components disposed in a fully completed 360 or 0 rotationaldegree position.

FIG. 13A is an example of a profile of speed of valve pin movementversus rotational position of the vertical portion of an eccentricelement of a speed reducing, torque increasing component driven atconstant speed by a motor in an apparatus according to the invention.

FIG. 13B is an example of a profile of force exerted on a driven valvepin versus vertically generated rotational position by an eccentricelement of a speed reducing, torque increasing component driven atconstant speed by a motor in an apparatus according to the invention.

FIG. 14A is a profile of constant speed of valve pin movement versusposition of a conventional non eccentric rotary to linear drive systemdriven at constant rotational speed by a motor in an injection moldingsystem.

FIG. 14B is an example of a profile of variable speed of valve pinmovement versus rotational position of an eccentric rotary to lineardrive system driven at constant rotational speed by a motor in aninjection molding system.

FIG. 15A is a profile similar to FIG. 14A.

FIG. 15B is a profile similar to FIG. 14B.

FIG. 16A is a profile similar to FIG. 14B.

FIG. 16B is a profile similar to FIG. 15B.

FIGS. 17A, 17B, 17C and 17D are examples of alternative gear assembliesfor changing rotational speed or torque of a rotary actuator.

DETAILED DESCRIPTION

FIG. 1 shows a generic system or apparatus 5 according to the inventioncomprising an injection molding machine IMM that feeds a selected fluid9 into an inlet 9 a that in turns feeds into a distribution channel 120of a heat manifold 60. As shown the manifold 60 is disposed between anupstream mounted top clamp plate 140 and a downstream mounted mold 70that forms a cavity 80 in which the part to be molded is formed frominjection fluid 9 that is routed into the cavity via downstream gate 110that communicates with nozzle channel 130 in which valve pin 100 isdisposed for controlled upstream and downstream reciprocal movementalong linear axis A between gate open and gate closed positions, thegate open position shown in FIG. 1 with respect to nozzle 132 and thegate closed position shown with respect to nozzle 134.

As shown in FIG. 1 a valve 50 is provided for controlling movement ofthe valve pin 100, the valve 50 comprising an electrically poweredactuator 200 typically comprised of an electric motor having a rotor 12rotatably driven by an electrically powered coil such as disclosed inU.S. Pat. No. 6,294,122 the disclosure of which is incorporated byreference as if fully set forth herein.

The valve pin 100 can be interconnected to or interengaged with a cammember 600 that is driven eccentrically around an output rotation axissuch as the axis 12 a of the motor rotor or the axis R3 a of a speedreducing, torque increasing device as described herein. One example ofan eccentric cam member 600 interconnected to the valve pin 100 is shownin FIGS. 5 and 6-11 . Another example of an eccentric cam member 600interengaged with a valve pin is shown in FIGS. 5A, 5B, 5C. The valvepin (100) can be maintained in engagement with the radial surface (600cs) under a spring force (SF) exerted by a spring (505). Theeccentricity of the cam member 600 enables variable speed and highertorque control over the linear drive movement of the pin 100 alonglinear axis A as described with reference to FIGS. 13-16 .

In the embodiment shown in FIG. 1-3 , the valve 50 includes a rigid,typically comprised of metal such as steel, elongated shaft 20 that iscoupled to the rotating rotor 12 via coupling 15 at an upstream end 22of the shaft 20 and a rotary to linear converter 40 that is coupled to adownstream end 24 of the elongated shaft 20 by coupling 30 such as auniversal joint. The elongated and rigid configuration of the shaft 20is selected so that the motor 200 and rotor 12 is necessarily disposedand mounted in a location or position that is isolated or insulated fromtransmission of heat from the heated manifold 60. The shaft 20 isselected to be comprised of a rigid metal material so that energy andtorque force R2 s derived from driven rotation R2 of the shaft 20 isreliably transmitted from the remotely mounted motor 200 to the rotaryto linear converter assembly 40. Such a rigid shaft 20 embodiment isdescribed in greater detail in published application no. WO2018/129015the disclosure of which is incorporated by reference in its entirety asif fully set forth herein.

In an alternative embodiment, the elongated shaft 20 can comprise anelongated flexible shaft 20 f as shown in FIG. 4 and described in detailin published application WO2017214387 the disclosure of which isincorporated by reference in its entirety as if fully set forth herein.

The converter 40 can comprise a mount or alignment support 40 a and asled or slide 43 to which is interconnected a valve pin 100. Thealignment support 40 a has a guide surface 40 as against which acomplementary surface 43 s of the sled or slide 43 slides as the sled 43is driven reciprocally along a linear path A by the eccentric drivecomponents that include the cam member 47, FIG. 1A. As shown in theembodiment of FIG. 8 , the sled 43 has freely rotatably wheels 43 r thatfacilitate upstream downstream sliding of the sled along surface 40 as.In an alternative embodiment, wheels 43 r are not necessary and thelateral surface 43 s can be adapted to slide directly against surface 40as without wheels. As shown in the FIGS. 1, 1A embodiment, the alignmentsupport 40 a is attached to a rotation speed reducer 42. The converter40 can be fixedly mounted to either the top clamp plate 140 as shown inFIG. 1 or to the heated manifold 60 as shown in FIG. 2 .

The converter 40 includes a drive or mounting wheel or disc 500 having arotational center 500 c to which is axially attached or interconnectedthe rotatable drive shaft 12 of the actuator 20 either directly orindirectly via rotatably interconnected elongated shaft 20, 20 f or aconnector shaft such as a splined shaft 42 s. With reference to FIGS. 5through 9 , the electrically powered rotatably driven rotor or driveshaft 12 of the motor is rotatably interconnected to the center 500 c ofthe drive wheel or disc 500 of the rotary to linear converter 40mechanism. An eccentrically mounted cam member 600, typically a freelyrotatable disc or wheel, is mounted to the rotatably driven disc orwheel 500 a selected eccentric off center distance ED from therotational center 500 c of the driven wheel or disc 500.

The electrically powered drive of the motor rotor 12 drivably rotates R3the drive wheel 500 at a controllably selectable speed and direction. Asshown in FIGS. 5-9 as the drive wheel 500 of the converter 40 isrotatably driven, the eccentrically mounted cam member 600 rotates R3around the center 500 c of the drive wheel 500. As shown, the converter40 includes a slide or sled 43 that is provided with a cam slot 43 slthat is attached to the support 40 a in an arrangement such that anoutside circumferential surface 600 cs, FIGS. 7A, 7B, 7C, of the cammember 600 engages a complementary interior cam surface 43 ss of theslide or sled 43 member. The cam surface 43 ss of the slide 43 isconfigured and adapted relative to the diameter D of the cam member 600and the eccentric distance ED to enable the outside surface 600 cs ofthe cam member 600 to forcibly engage the interior surface 43 ss of theslide 43 and thus cause the slide 43 to be forcibly driven in a lineardirection up and down or back and forth in or along a linear directionor axis A, FIGS. 5-9 as the cam member 600 is eccentrically drivablyrotated R3 around the center of driven disc or wheel member 500. Asshown, valve pin 100 is fixedly attached to the driven slide or sledmember 43 in an arrangement such that the valve pin 100 is linearlydriven together with the linear movement A of the slide 43.

Because of the eccentric mounting of the cam member 600, the linear oraxial speed, A31, A32, A33 of the valve pin 100 and sled 43 along thelinear path A varies A31, A32, A33 according to the rotational orangular position of the cam member 600 during the course of a constantrotational speed R3. The linear or axial speed A32 is at a maximum whenthe cam member 600 is at the ninety degree rotational position shown inFIG. 7B and at a lesser speed when the cam member 600 is at the 45degree position of FIG. 7A and the 135 degree rotational position shownin FIG. 7C. Similarly with respect to the eccentric cam embodiment ofFIGS. 5A, 5B, 5C, the linear or axial speed A32 of the valve pin 100 isat a maximum when the eccentric or eccentrically configured cam surface600 cs of disk 500 is in the ninety degree position, FIG. 5B, and thelinear speeds A31 and A33 are less than the maximum when the eccentriccam surface 600 cs is in the 0 degree, FIG. 5A, and 45 degree, FIG. 5C,positions.

Conversely because of the eccentric mounting of the cam member 600, thetorque force, T31, T32, T33 exerted by the eccentric cam 600 on thevalve pin 100 and sled 43 along the linear path A varies T31, T32, T33according to the rotational or angular position of the cam member 600the rotational speed R3 is constant. The torque force is at a minimumwhen the cam member 600 is disposed at the ninety degree rotationalposition shown in FIG. 7B and at a higher torque when the cam member 600is at the 45 degree position of FIG. 7A and the 135 degree rotationalposition shown in FIG. 7C. Similarly with respect to the eccentric camembodiment of FIGS. 5A, 5B, 5C, the torque force T32 exerted by the camsurface 600 cs on the valve pin 100 is at a minimum when the eccentricor eccentrically configured cam surface 600 cs of disk 500 is in theninety degree position, FIG. 5B, and the torque force T31, T33 aregreater than the minimum when the eccentric cam surface 600 cs is in the0 degree (at maximum torque force), FIG. 5A, and 45 degree, FIG. 5C,positions.

The absolute highest torque position is a position where the cam isdisposed in the absolute maximum moment position which is typically the0 degree position, MM1, or the 180 degree position, MM2. The 0 degreeposition is also shown in FIG. 5A, the absolute maximum moment andabsolute minimum torque position.

FIGS. 6B, 6C, 6D, 6E, 6F show various preferred embodiments whererotation of the cam member 600 is limited to travelling through an arcsegment that is something less than the full 360 degrees that the shaftor output device would otherwise rotate, such as between 70 degreesabove and below the 90 and 270 degree positions, most preferably between40 degrees above and below the 90 and 270 degree positions.

In such embodiments, the cam device (600) is eccentrically disposed ormounted off center a selected distance (ED, R) from the output rotationaxis (12 a, R3 a) in an arrangement such that when the shaft (12) orrotation device (16, 430, 500) is rotatably driven, the cam member (600)is eccentrically rotatably drivable around the output rotation axis (12a, R3 a) to selectable angular positions above and below either a 270degree position or a 90 degree position, FIGS. 6A, 6B, 6C.

In such a preferred embodiment, a controller (1000), FIGS. 1, 6A, 11 isinterconnected to the shaft (12) or output rotation device (16, 430,500), the controller (1000) including an algorithm that controllablylimits rotation of the shaft (12) or output rotation device (16, 430,500) during the course of an entire injection cycle to angular positionsbetween about 70 degrees above and 70 degrees below the 270 degreeposition, FIG. 6B, or between about 70 degrees above and 70 degreesbelow the 90 degree position, FIG. 6B. A preselected angular positionbetween the 270 or 90 degree position and 70 degrees above defines afully open valve pin position (PFO) and a preselected angular positionbetween the 270 or 90 degree position and 70 degrees below defines avalve pin position where the gate is closed (PFC).

As shown in FIG. 6B, slide, sled or linear travel device (43, 40) isadapted to guide the valve pin along a linear path of travel (A, AS).The rotary to linear converter device (40, 43) can include stops orlinear travel limiters (not shown) that are fixed to the alignmentsupports 40 a of the rotary to linear converter 40 or otherwise fixedlyattached relative to the sled 43. The stops are typically mounted andadapted to limit linear travel of the slide or sled 43 such that whenthe cam member 600 is rotated to a preselected maximum angular position70 degrees or less above or below the 270 (or 90) degree position,travel of the cam 600 and the valve pin is stopped. Typically, suchpreselected maximum angular positions above and below the 270 or 90degree positions are selected so as to define a correspondingpreselected valve fully open position (PFO) and a corresponding valvefully closed position (PFC).

Most preferably, the algorithm controllably limits rotation of the shaft(12) or output rotation device (16, 430, 500) during the course of anentire injection cycle to angular positions between about 40 degreesabove and 40 degrees below the 270 degree position or between about 40degrees above and 40 degrees below the 90 degree position wherein apreselected angular position between 40 degrees above the 270 or 90degree position defines the fully open valve pin position (PFO) and apreselected angular position 40 below the 270 or 90 degree positiondefines the valve pin position where the gate is closed (PFC).

An alternative manner of describing how rotation of the cam 600 islimited is that the algorithm of the controller 1000 limits rotation ofthe shaft (12) or output rotation device (16, 430, 500) to selectableangular positions that create a moment arm M that extends between aselected minimum moment arm M2, FIG. 6D, and a selected maximum momentarm, M1, FIG. 6C, the selectable angular positions being between 70degrees above and 70 degrees below the preselected angular position (270degrees, FIG. 6B) that corresponds to the selected maximum moment armM1. Typically the absolute maximum moment arm M1 exists when therotational or angular position of the cam 600 is disposed at 270 degreesor 90 degrees, although other angular positions could be preselected todefine or correspond to the absolute maximum moment arm position.

FIG. 6D shows the cam member 600 rotated to a position 40 degrees below270 degrees at which the valve pin is disposed in a fully gate closedposition where flow of fluid through the gate is stopped. As discussedbelow, a frictional or mechanical stop device can be provided such thatthe valve pin is mechanically stopped in the valve closed position.

FIG. 6E shows the sled 43 rotated to an angular position of 40 degreesabove the 270 degree rotational position at which the valve pin isdefined and selected as being disposed in the fully valve pin and gatefully open position. As discussed below, a frictional or mechanical stopdevice can be provided such that the valve pin is mechanically stoppedin the valve fully open position.

Similarly FIG. 6D shows the sled 43 rotated to an angular position of 40degrees below the 270 degree rotational position at which the valve pinis defined and selected as being disposed in the valve pin and gatefully closed position. As discussed, a frictional or mechanical stopdevice can be provided such that the valve pin is mechanically stoppedin the valve fully closed position.

The 270 degree position is one position at which the cam member 600 andassociated elements of the drive system 200 is disposed at its absolutemaximum moment arm position. The mirror image of the FIGS. 6C, 6D and 6Eembodiments is where the cam member is rotated to a 90 degree rotationalposition at which the cam member 600 and associated elements of thedrive system 200 are also disposed at an absolute maximum moment armposition.

FIGS. 6E, 6F show an embodiment where the cam member 600, the slide 43,the mount 40 are mounted and adapted such that the outer circumferentialsurface 600 cs of the cam member 600 is drivable to a selectable angularposition that is adapted to cause the cam outer surface 600 cs to engageand forcibly push against the slide or sled or travel member surface 43hss with a degree of radially directed force RF that causes the outersurface 43 s or bearings disposed between the outer surface 43 s of thetravel member 43 and opposing surface 40 as to forcibly engage againstthe complementary surface 40 as of the support 40 such that the slide,sled or travel member 43 is mechanically forced to come to a hard stopas a result of frictional engagement between the outer surface 43 s orbearings disposed between the outer surface 43 s of the travel member 43and opposing surface 40 as of the support 40. As can be readilyimagined, balls, ball bearings or the like can be disposed between thesurfaces 43 s and 40 as for enabling ready linear sliding of one surfacealong the other in which case the force RF created by the hard stoprotation of the cam 600 would be exerted between the balls, ballbearings or the like and the surfaces 43 s and 40 as to effect africtional force that mechanically prevents the surfaces 43 s and 40 asfrom moving relative to each other and thus mechanically stops linearmovement of the slide or sled 43 and thus also stops movement of thevalve pin 100.

Alternatively an outer surface 43 s of the slide 43 could be adapted tofrictionally engage against the surface of another fixedly mounted stopmember (not shown) that is fixedly interconnected to the assembly 200relative to the sled, slide or linear travel member 43. The angular orlinear location of the hard stop position is typically selected tocorrespond to the angular positions of the cam member 600 thatcorrespond to the linear valve pin open PFO and valve pin closed PFCpositions.

The selectable angular positions above and below the maximum moment armposition M1 are preferably selected to be between about 40 degrees aboveand about 40 degrees below the angular position that corresponds to theselected maximum moment arm M1 position, such positions beingalternatively between about 70 degrees above and 70 degrees below theangular position that corresponds to the selected maximum moment arm M1position.

FIGS. 13A, 14B, 16A show how the linear or axial speed A3X of the sledand valve pin vary with all 0-360 degree rotational positions of the cammember 600 when the rotational speed of the mounting or drive disk 500is constant.

Similarly the torque force T3X, FIG. 6 , exerted by the eccentric cam600 on the valve pin 100 in different rotational positions such as inFIGS. 7A, 7B, 7C varies T31, T32, T33. FIGS. 13B, 15B, 16B show how thetorque force T3X of the sled and valve pin vary with all 0-360 degreerotational positions of the cam member 600 when the rotational speed R3of the mounting or drive disk 500 is constant.

When the system 5 is assembled and the heated manifold 60 is heated to atypical high operating temperature, the manifold 60 body will tend tophysically expand in size thus causing translational movement of thebody of the manifold 60 relative to the top clamp plate 140 and the moldbody 70. Similarly components of the valve assembly such as theconverter housing 40 h and valve pin 100 that may be mounted to theheated manifold will translationally move in several directions such aslaterally LS, axially AS and from front to back FBS, FIG. 2 , namely ina direction in and out of the page as shown in FIG. 2 , while the motor200 is stationarily mounted on the top clamp plate 140 or to anotherstationary structure of the system 5. To accommodate such in and out orfront to back FBS movement in an embodiment where the actuator 200 isremotely mounted relative to the converter 40, the interconnectingjoints 15, 30 are flexible such that the joints 15, 30 are preferablyadapted to enable the shaft 20 to pivot in or along the axial AS orlateral LS or FBS directions or axes together with movement of thehousing 40 or motor 200 along the same AS, LS or FBS directions or axes.Joints 15, 30 can comprise a universal joint that include hinges such ashinges 15 h 1, 15 h 2 that may be pivotably connected to each other by across shaft 15 cs. A cross shaft connection can connect the hinge suchthat the two hinges that make up a complete hinge can co rotate witheach other along their respective rotational axes and simultaneouslyalso to pivot in the FBS axis or direction relative to each other aroundthe axis of the connecting cross shaft while still continuing to corotate when the shaft 20, particularly a rigid shaft, is being rotatablydriven. Thus any components that may be mounted to the manifold 60 suchas the converter housing 40 or valve pin 100 may translationally moverelative to the motor 200 when the system is brought to operatingtemperature.

As shown in FIG. 8 the driven wheel or disc component 500 is typicallymounted on the forward face 500 m of the driven rotating disc or wheelcomponent 700 of a speed reducing device 42 which is reduced inrotational speed relative to the rotational speed of the rotor or driveshaft 12 of the actuator 200.

The rotational speed reducing device 46 preferably comprises a strainwave gear that includes a rotatable elliptical or other non circularshaped such as a three node containing shaped disk or ring thatgenerates a reduction in rotation speed output relative to the rotationspeed of the input rotor. The strain wave gear is typically comprised ofthree basic components: a wave generator, a flex spline and a circularspline. The wave generator is typically made up of an elliptical orother non circular shaped such as a three node containing shaped diskcalled a wave generator plug and an outer ball bearing, the outerbearing having an elliptical or other non circular shaped such as athree node containing shape as well. The flex spline is typically shapedlike a shallow cup. The circumferential side walls of the spline arevery thin, but the bottom is relatively rigid. This results insignificant flexibility of the walls at the open end due to the thinwall, and in the closed side being quite rigid and able to be tightlysecured to an output shaft. Teeth are positioned radially around theoutside of the flex spline. The flex spline fits tightly over the wavegenerator, so that when the wave generator plug is rotated, the flexspline deforms to the shape of a rotating ellipse or other non circularshape such as a three node containing shape and does not slip over theouter elliptical or other non circular shaped such as a three nodecontaining shaped ring of the ball bearing. The ball bearing lets theflex spline rotate independently to the wave generator's shaft. Thecircular spline is a rigid circular ring with teeth on the inside. Theflex spline and wave generator are placed inside the circular spline,meshing the teeth of the flex spline and the circular spline. Becausethe flex spline is deformed into an elliptical or other non circularshaped such as a three node containing shape, its teeth only actuallymesh with the teeth of the circular spline in two regions on oppositesides of the flex spline (located on the major axis of the ellipse orother non circular shaped such as a three node containing shape).

As the wave generator plug rotates, the flex spline teeth which aremeshed with those of the circular spline change position. The major axisof the flex spline's ellipse or other non circular shaped such as athree node containing shape rotates with wave generator, so the pointswhere the teeth mesh revolve around the center point at the same rate asthe wave generator's shaft. The key to the design of the strain wavegear is that there are fewer teeth (often for example two fewer) on theflex spline than there are on the circular spline. This means that forevery full rotation of the wave generator, the flex spline would berequired to rotate a slight amount (two teeth in this example) backwardrelative to the circular spline. Thus the rotation action of the wavegenerator results in a much slower rotation of the flex spline in theopposite direction. For a strain wave gearing mechanism, the gearingreduction ratio can be calculated from the number of teeth on each gear.

The apparatus most preferably includes a position sensor EN, FIGS. 1, 2that senses a rotational position of the rotor 12 of the electricactuator or motor 200 or a position sensor PS, FIG. 10 , that senses thelinear position of the valve pin 100 or a linearly moving member such assled 43 that moves together with linear movement of the valve pin 100.In the FIGS. 1, 2 embodiment, the position sensor EN typically comprisesan encoder that senses the rotational position of the rotor 12 or arotating element of the strain wave gear 400 such as the flexible spline430 which in turn corresponds to the linear position of the pin 100. Inthe FIG. 10 embodiment the linear position sensor PS typically comprisesa Hall Effect sensor (HES or H.E.S.) that senses a change in a magneticfield generated by a magnet that is mounted to and linearly movestogether with linear movement of the pin 100, the sensor convertingchange in magnetic field to position of the valve pin 100. As shown inFIG. 10 the magnet M is mounted to the sled 43 and moves linearlytogether therewith. The detector PS thus senses any magnetic fieldgenerated by the magnet M and any changes in the field as the magnetmoves linearly relative to the linear position of the sensor PS which isstationarily mounted relative to the sliding sled 43 in field detectionproximity to the magnet M.

In the embodiments shown, the strain wave gear 400, FIGS. 10, 11, 12A,12B, 12C, 12D is comprised of the wave generator or thin walled bearing460 that is mounted within and against the inner circumferential wall ofthe flex spline 430 that is in turn mounted within the inner splinedcircumference of a rigid circular spline 448 as shown for example inFIGS. 10, 11, 12A, 12B, 12C, 12D. FIG. 12A is a schematic end view ofthe speed reducer assembly of FIG. 11 at a starting point of arevolution of the actuator shaft 12. A shaft position indicator PS showsthat nodes 482 formed on the hub 472 are vertically aligned 180 degreesapart from each other forming an elliptical or other non circular shapedsuch as a three node containing shaped circumferential surface. An innerbearing race 464 pressed on the elliptical or other non circular shapedsuch as a three node containing surface of the hub 472 either having ortaking a shape complementary to the cam or elliptical or other noncircular shaped such as a three node containing surfaces of the hub 472and imparting forces 470 through the ball bearings 466 to thecomplementarily shaped outer race 462 that is also generally ellipticalor other non circular shaped such as a three node containing shape andto the flex spline teeth 444, forcing them to mesh with the ring gearteeth 446 as the cam turns on shaft 12. A flex spline tooth 444 a isshown as aligned with reference point P on the ring gear. FIG. 12B showsthe shaft 12 rotating (R) 90 degrees C.W. FIG. 12C shows the shaft 12rotated 180 degrees C.W. The alignment of tooth 444 a has now shifted tobe one tooth short of alignment with point P. FIG. 12D shows the shaft12 rotated 360 degrees C.W. The alignment of tooth 444 a has now shiftedto be two teeth short of alignment with point P. This means that theflex spline has rotated (R) slightly less than the input shaft 12. Thisallows for high gear ratios such as up to 99/1.

The input shaft comprises the motor shaft 12 that rotates around theshaft axis 12 a, the outer surface of which is compressibly mated withthe inner circumferential surface 480 of the shaft receiving bore 474 ofthe hub of the gear. In the embodiment shown in FIGS. 10, 11, 12A, 12B,12C, 12D the output shaft or disc being the inner race 414 of an outputbearing 410, the interface surface 420 of the inner race 414 beingattached to a complementary end surface 432 of the flexspline 430. Thestrain wave gear as shown is comprised of a housing 400 on which aslewing ring bearing is mounted at the front end. The outer race 412 ofthe bearing is bolted to the housing and the inner race 414 is part ofan armature 418 which is supported by rollers 416. The slewing ringbearing provides superior stability against any forward to backwardmovement of the armature as it turns in the housing. The forward end orface 422 of the armature has a bolt pattern 424 on which the drive disc500 is fastened by screws 428 which pass through bolt pattern 502. Thecam member 600 is bolted to armature 418 through one of the holes inbolt pattern 502 of the drive disc 500 and is rotated eccentrically adistance ED around output rotation axis R3 a. The shoulder bolt 602clamps a boss 604 to the disc 500 that is drivably rotated around thegear reducer rotation axis R3 a, FIGS. 10, 11 . The boss forms an innerrace for roller bearings 606. The outer race 608 has an outer surface600 cs that drives the sled 43 up and down. At the rearward end 420 ofthe armature there is a bolt pattern 426 to which the flex spline 430 isbolted. The flex spline is cup shaped. The forward end 432 is closed andhas a bolt pattern 436 for securing the end of the flex spline to thearmature by means of clamping plate 436 and bolts 438. The sidewall 440of the flex spline is thin for flexibility but retains good torsionalstrength. The rearward end of the cup shape 442 is open to receive thewave generator 460. The exterior surface of the rim has gear teeth 444which selectively engage teeth 446 on the ring gear 448 as the wavegenerator rotates. The wave generator is mounted on the motor driveshaft 12 by hub 472. Hub 472 has an aperture 474 lined with compressiblewedge shaped sleeves 480. When screws 478 are tightened, they force theclamping ring 476 rearward compressing the sleeves and self-centeringand clamping the hub to the shaft 12 without the use of Allen set screwsor keyways for smoother operation. The wave generator 460 is composed ofan oval shaped cam formed on hub 472 on which is mounted by force fit, aball bearing assembly with a flexible inner race that is force fit onthe cam portion of hub 472. Lobes 482 on the hub form the inner race 464into a cam with two lobes 468 formed 180 degrees apart in an oval shape.The outer race 462 can be rigid in the form an ellipse or other noncircular shaped such as a three node containing shape complementary tothe elliptical shape or other non circular shaped such as a three nodecontaining shape of the hub 472 and the inner race 464 or can be thinand flexible so it can conform to the shape of the cam such that itprojects outward (arrows 470, FIGS. 12A & 12B) together with ballbearings 466 as the shaft 12 rotates, to force the gear teeth 444, 446to mesh at locations 450. The teeth 444 at locations 452 flex inwardafter the lobes have passed to allow clearance for one or more of theteeth 444 to skip the ring gear teeth 446 and allow the flex spline 430to rotate in relation to the ring gear 448 as dictated by the gear ratioand number of teeth.

The nature of the arrangement of the operative components (wavegenerator, flex spline, circular spline) of the strain wave gear 46, 400in a nested fashion provide a physical device depth GD, diameter DIA orphysical size that is adapted to be compact and space efficient enoughor sufficient to enable the device to be mounted to the housing of therotary to linear converter 40, and to be readily mountable to anddismountable from, alone or together with the rotary to linearconverter, either one or the other of the top clamping plate and theheated manifold.

Alternatively the speed reducing, torque increasing device can comprisean assembly such as shown in FIGS. 17A (worm gear assembly), 17B (spurgear assembly), 17C (planetary gear assembly) where the rotor 12 of themotor 200 is connected to and rotates the highest speed rotating gear orgear tooth containing component 800 of the assembly 2200 and theintermediate shaft is connected to and rotated by the highest rotatinggear or gear tooth containing component 700 of the assembly 2200 toeffectively reduce the rotational speed and increase the torque outputof the rotor 12 that is transmitted to the output shaft 16 o that isdriven at a reduced speed R3 and higher torque R3 s. Other assembliessuch as helical gear assemblies, FIG. 17D, or belts and pulleyarrangements and assemblies can be used to affect such speed changingand torque changing.

An injection molding apparatus (5) comprising an injection moldingmachine (IMM), a heated manifold (60) that receives injection fluid (9)from the injection molding machine and distributes the injection fluidthrough a fluid distribution channel (120), a mold (70) having a cavity(80) and one or more valves (50) having a valve pin (100) that controlinjection of the injection fluid (9) into the mold cavity, the one ormore valves (50) being comprised of:

an electrically driven actuator (200) having a rotatable rotor or motorshaft (12) and a strain wave gear (46) that includes a generallyelliptical or other non circular shaped member interconnected to thedrive shaft or rotor (12) and adapted to be rotatably driven at aselected lower rotational speed relative to a rotational speed of thedrive shaft or rotor (12) and drivably interconnected to the valve pin(100) such that the valve pin (100) is driven along a linear path oftravel,

a position sensor adapted to sense rotational positon of the rotatablerotor or motor shaft or the generally elliptical or other non circularshaped member or adapted to sense linear position of the valve pin(100).

The position sensor can comprise an encoder (EN) that is mounted andadapted to sense rotational position of the valve pin 100

The position sensor can alternatively comprises a hall effect sensor(PS) that detects a magnetic field generated by a magnet (M) associatedwith linear motion of the valve pin (100).

What is claimed is:
 1. An injection molding apparatus (5) comprising an injection molding machine (IMM), a heated manifold (60) that receives injection fluid (9) from the injection molding machine and distributes the injection fluid through a fluid distribution channel (120), a mold (70) having a cavity (80) and one or more valves (50) having a valve pin (100) that controls injection of the injection fluid (9) into the mold cavity, the one or more valves (50) being comprised of: an electrically driven actuator (200) having a driven rotatable rotor drivably rotatably interconnected to a shaft (12) or to an output rotation device (16, 430, 500) that is rotatably drivable 360 degrees around an output rotation axis (12 a, R3 a), a rotary to linear converter device that includes an eccentric (600) that is eccentrically disposed or mounted off center a selected distance (ED, R) from the output rotation axis (12 a, R3 a) in an arrangement such that when the shaft (12) or rotation device (16, 430, 500) is rotatably driven, the eccentric (600) is eccentrically rotatably drivable around the output rotation axis (12 a, R3 a) to selectable angular positions above and below either a 270 degree position or a 90 degree position, a controller interconnected to the shaft (12) or output rotation device (16, 430, 500), the controller including an algorithm that controllably limits rotation of the shaft (12) or output rotation device (16, 430, 500) during the course of an entire injection cycle to angular positions between about 70 degrees above and 70 degrees below the 270 degree position or between about 70 degrees above and 70 degrees below the 90 degree position, the pin or shaft (100) being interconnected to or interengaged with the driven eccentric (600) in an arrangement such that the pin or shaft (100) is driven reciprocally along a linear path of travel (A) as the eccentric (600) is eccentrically rotatably driven.
 2. The apparatus of claim 1 wherein a preselected angular position between the 270 or 90 degree position and 70 degrees above defines a fully open valve pin position (PFO) and a preselected angular position between the 270 or 90 degree position and 70 degrees below defines a valve pin position where the gate is closed (PFC).
 3. The apparatus of claim 1 wherein the eccentric comprises a cam member (600), the rotary to linear converter device including a slide or sled (43) interconnected to the drive shaft or rotor (12), the slide or sled (43) having a cammed slot (43 sl) having a slot surface (43 ss) adapted to engage an exterior surface (600 cs) of the eccentric (600) to cause the sled or slide (43) to move along the linear path of travel (A) as the eccentric (600) is eccentrically rotatably driven around the output rotation axis (12 a, R3 a).
 4. An apparatus according to claim 1 wherein the rotary to linear converter device is adapted to mechanically or frictionally stop or limit linear travel of the valve pin (100) at or to selectable linear positions.
 5. An apparatus according to claim 1 wherein the cam member (600), slide or sled (43) or associated mounts (40) are adapted to exert a radial force (RF) between the slide or sled (43) and a complementary fixed surface (40 as) at selectable rotational or angular positions of the cam member (600), the radial force (RF) being sufficient to stop rotational movement of the cam member (600) or to stop linear movement of the slide or sled (43).
 6. An apparatus according to claim 1 further including a rotational speed reducing mechanism (46) interconnected to the drive shaft or rotor (12) of the actuator (200), the rotational speed reducing mechanism (46) being comprised of a rotatably driven generally elliptical or other non-circular shaped device (430, 472) or one or more rotatably driven gears (430, 700) interconnected to the drive shaft or rotor (12) in an arrangement such that rotation of the drive shaft or rotor (12) is transmitted to an output rotation device (16, 430, 500) to cause the output rotation device (16, 430, 500) to be rotatably driven at a selected lower rotational speed relative to a rotational speed of the drive shaft or rotor (12).
 7. An apparatus according to claim 6 wherein the rotational speed reducing mechanism comprises a strain wave gear.
 8. An apparatus according to claim 1 wherein the electrically driven actuator (200) is mounted in a remote location or position relative to the heated manifold (60) such that the electrically driven actuator (200) is insulated or isolated from thermal communication with the heated manifold (60).
 9. An apparatus according to claim 1 wherein an elongated shaft (20, 20 f) drivably interconnects the rotatable output shaft (12) or the output rotation device (16, 430, 500) to a linear converter (40) that is interconnected to the pin or shaft (100) to convert rotation of the shaft (12) or the output rotation device (16, 430, 500) to linear motion and drive the pin or shaft (100) linearly.
 10. An apparatus according to claim 9 wherein the elongated shaft has a length (CL) sufficient to mount the actuator (200) in a position or location remote from the heated manifold (60) such that the actuator (200) is isolated from substantial heat communication with the heated manifold (60) wherein the actuator remains interconnected to the valve pin (100) via the elongated shaft (20, 20 f).
 11. An apparatus according to claim 1 wherein an elongated cable or shaft (20 f) having a length (CL) and a cable axis (CA) that is flexibly bendable along at least a portion of the cable axis (CA) into a curved or curvilinear configuration (CF) interconnects the shaft (12) or the output rotation device (16, 430, 500) to a rotary to linear converter (40) that is interconnected to the pin or shaft (100) to convert rotation of the output shaft (12) or the output rotation device (16, 430, 500) to linear motion and drives the pin or shaft (100) linearly.
 12. An apparatus according to claim 1 wherein the algorithm controllably limits rotation of the shaft (12) or output rotation device (16, 430, 500) during the course of an entire injection cycle to angular positions between about 40 degrees above and 40 degrees below the 270 degree position or between about 40 degrees above and 40 degrees below the 90 degree position wherein a preselected angular position between 40 degrees above the 270 or 90 degree position defines the fully open valve pin position (PFO) and a preselected angular position 40 below the 270 or 90 degree position defines the valve pin position where the gate is closed (PFC).
 13. An apparatus according to claim 1 wherein the valve pin (100) is maintained in engagement with a radial surface (600 cs) under a spring force (SF).
 14. A method of injecting a selected injection fluid (9) into a cavity (80) of a mold (70) in an injection molding apparatus (5) comprised of an injection molding machine (IMM), a heated manifold (60) that receives injection fluid (9) from the injection molding machine and distributes the injection fluid through a fluid distribution channel (120), a mold (70) having a cavity (80) and one or more valves (50) having a valve pin (100) that controls injection of the injection fluid (9) into the mold cavity, the method comprising: selecting an electrically driven actuator (200) having a driven rotatable rotor drivably rotatably interconnected to an output shaft (12) or to an output rotation device (16, 430, 500) that is rotatably driven around an output rotation axis (12 a, R3 a), disposing or mounting an eccentric (600) eccentrically off center a selected distance (ED, R) from the output rotation axis (12 a, R3 a) in an arrangement such that when the shaft (12) or rotation device (16, 430, 500) is rotatably driven, the eccentric (600) is eccentrically rotatably driven around the output rotation axis (12 a, R3 a), controllably rotating the shaft (12) or output rotation device (16, 430, 500) during the course of an entire injection cycle to angular positions between about 70 degrees above and 70 degrees below the 270 degree position or between about 70 degrees above and 70 degrees below the 90 degree position, wherein a preselected angular position between the 270 or 90 degree position and 70 degrees above defines a fully open valve pin position (PFO) and a preselected angular position between the 270 or 90 degree position and 70 degrees below defines a valve pin position where the gate is closed (PFC), interconnecting to or interengaging with the pin or shaft (100) the driven cam member (600) in an arrangement such that the pin or shaft (100) is drivable reciprocally along a linear path of travel (A) as the eccentric (600) is eccentrically rotatably driven, controllably operating the electrically driven actuator to drive the pin or shaft (100).
 15. A method according to claim 14 wherein a preselected angular position between the angular position that corresponds to the selected maximum moment arm and 70 degrees above defines a fully open valve pin position (PFO) and a preselected angular position between the angular position that corresponds to the selected maximum moment arm and 70 degrees below defines a valve pin position where the gate is closed (PFC).
 16. An injection molding apparatus (5) comprising an injection molding machine (IMM), a heated manifold (60) that receives injection fluid (9) from the injection molding machine and distributes the injection fluid through a fluid distribution channel (120), a mold (70) having a cavity (80) and one or more valves (50) having a valve pin (100) that controls injection of the injection fluid (9) into the mold cavity, the one or more valves (50) being comprised of: an electrically driven actuator (200) having a driven rotatable rotor drivably rotatably interconnected to a shaft (12) or to an output rotation device (16, 430, 500) that is rotatably drivable 360 degrees around an output rotation axis (12 a, R3 a), a rotary to linear converter device that includes an eccentric (600) that is eccentrically disposed or mounted off center a selected distance (ED, R) from the output rotation axis (12 a, R3 a) in an arrangement such that when the shaft (12) or rotation device (16, 430, 500) is rotatably driven, the eccentric (600) is eccentrically rotatably drivable around the output rotation axis (12 a, R3 a) to selectable angular positions above and below either a 270 degree position or a 90 degree position, a controller interconnected to the shaft (12) or output rotation device (16, 430, 500), the controller including an algorithm that controllably limits rotation of the shaft (12) or output rotation device (16, 430, 500) during the course of an entire injection cycle to selectable angular positions that create a moment arm that extends between a selected minimum moment arm and a selected maximum moment arm, the selectable angular positions being between 70 degrees above and 70 degrees below an angular position that corresponds to the selected maximum moment arm, the pin or shaft (100) being interconnected to or interengaged with the driven eccentric (600) in an arrangement such that the pin or shaft (100) is driven reciprocally along a linear path of travel (A) as the eccentric (600) is eccentrically rotatably driven.
 17. The apparatus of claim 16 wherein a preselected angular position between the angular position that corresponds to the selected maximum moment arm and 70 degrees above defines a fully open valve pin position (PFO) and a preselected angular position between the angular position that corresponds to the selected maximum moment arm and 70 degrees below defines a valve pin position where the gate is closed (PFC).
 18. An apparatus according to claim 16 wherein the selectable angular positions are between 40 degrees above and 40 degrees below the angular position that corresponds to the selected maximum moment arm.
 19. An apparatus according to claim 16 wherein a first selected angular position disposed between the angular position that corresponds to the maximum moment arm and 70 degrees above the angular position that corresponds to the maximum moment arm defines a valve pin fully open position and wherein a second selected angular position disposed between the angular position that corresponds to the maximum moment arm and 70 degrees below the angular position that corresponds to the maximum moment arm defines an end of stroke, valve pin closed or gate closed position.
 20. An apparatus according to claim 16 wherein a first selected angular position disposed between the angular position that corresponds to the maximum moment arm and 40 degrees above the angular position that corresponds to the maximum moment arm defines a valve pin fully open position and wherein a second selected angular position disposed between the angular position that corresponds to the maximum moment arm and 40 degrees below the angular position that corresponds to the maximum moment arm defines an end of stroke, valve pin closed or gate closed position.
 21. An apparatus according to claim 16 wherein the eccentric comprises a cam member (600), the rotary to linear converter device including a slide or sled (43) interconnected to the drive shaft or rotor (12), the slide or sled (43) having a cammed slot (43 sl) having a slot surface (43 ss) adapted to engage an exterior surface (600 cs) of the eccentric (600) to cause the sled or slide (43) to move along the linear path of travel (A) as the eccentric (600) is eccentrically rotatably driven around the output rotation axis (12 a, R3 a).
 22. An apparatus according to claim 16 wherein the rotary to linear converter device is adapted to mechanically or frictionally stop or limit linear travel of the valve pin (100) at or to selectable linear positions.
 23. An apparatus according to claim 16 wherein the cam member (600), slide or sled 43 or associated mounts 40 can be adapted to exert a radial force (RF) between the slide or sled (43) and a complementary fixed surface (40 as) at selectable rotational or angular positions of the cam member (600), the radial force (RF) being sufficient to stop rotational movement of the cam member (600) or to stop linear movement of the slide or sled (43).
 24. An apparatus according to claim 16 further including a rotational speed reducing mechanism (46) interconnected to the drive shaft or rotor (12) of the actuator (200), the rotational speed reducing mechanism (46) being comprised of a rotatably driven generally elliptical or other non-circular shaped device (430, 472) or one or more rotatably driven gears (430, 700) interconnected to the drive shaft or rotor (12) in an arrangement such that rotation of the drive shaft or rotor (12) is transmitted to an output rotation device (16, 430, 500) to cause the output rotation device (16, 430, 500) to be rotatably driven at a selected lower rotational speed relative to a rotational speed of the drive shaft or rotor (12).
 25. An apparatus according to claim 16 wherein the rotational speed reducing mechanism comprises a strain wave gear.
 26. An apparatus according to claim 16 wherein the electrically driven actuator (200) is mounted in a remote location or position relative to the heated manifold (60) such that the electrically driven actuator (200) is insulated or isolated from thermal communication with the heated manifold (60).
 27. An apparatus according to claim 16 wherein an elongated shaft (20, 20 f) drivably interconnects the rotatable output shaft (12) or the output rotation device (16, 430, 500) to a linear converter (40) that is interconnected to the pin or shaft (100) to convert rotation of the output shaft (12) or the output rotation device (16, 430, 500) to linear motion and drive the pin or shaft (100) linearly.
 28. An apparatus according to claim 16 wherein the elongated shaft has a length (CL) sufficient to mount the actuator (200) in a position or location remote from the heated manifold (60) such that the actuator (200) is isolated from substantial heat communication with the heated manifold (60) wherein the actuator remains interconnected to the valve pin (100) via the elongated shaft (20, 20 f).
 29. An apparatus according to claim 16 wherein an elongated cable or shaft (20 f) having a length (CL) and a cable axis (CA) that is flexibly bendable along at least a portion of the cable axis (CA) into a curved or curvilinear configuration (CF) interconnects the rotatable output shaft (12) or the output rotation device (16, 430, 500) to a rotary to linear converter (40) that is interconnected to the pin or shaft (100) to convert rotation of the output shaft (12) or the output rotation device (16, 430, 500) to linear motion and drives the pin or shaft (100) linearly.
 30. An apparatus according to claim 16 wherein the cam member (600) comprises a disk, wheel, pin or projection (600 p) projecting axially from a rotatable member (500) that is controllably rotatable around a rotation axis (R3 a) or comprises a radial surface (600 cs) of a rotatable member (500) controllably rotatable around a rotation axis (R3 a).
 31. An apparatus according to claim 16 wherein the valve pin (100) is maintained in engagement with a radial surface (600 cs) under a spring force (SF).
 32. A method of injecting a selected injection fluid (9) into a cavity (80) of a mold (70) in an injection molding apparatus (5) comprised of an injection molding machine (IMM), a heated manifold (60) that receives injection fluid (9) from the injection molding machine and distributes the injection fluid through a fluid distribution channel (120), a mold (70) having a cavity (80) and one or more valves (50) having a valve pin (100) that controls injection of the injection fluid (9) into the mold cavity, the method comprising: selecting an electrically driven actuator (200) having a driven rotatable rotor drivably rotatably interconnected to an output shaft (12) or to an output rotation device (16, 430, 500) that is rotatably driven around an output rotation axis (12 a, R3 a), disposing or mounting an eccentric (600) eccentrically off center a selected distance (ED, R) from the output rotation axis (12 a, R3 a) in an arrangement such that when the shaft (12) or rotation device (16, 430, 500) is rotatably driven, the eccentric (600) is eccentrically rotatably driven around the output rotation axis (12 a, R3 a), controllably rotating the shaft (12) or output rotation device (16, 430, 500) during the course of an entire injection cycle to selectable angular positions that create a moment arm that extends between a selected minimum moment arm and a selected maximum moment arm, the selectable angular positions being between 70 degrees above and 70 degrees below an angular position that corresponds to the selected maximum moment arm, interconnecting to or interengaging with the pin or shaft (100) the driven cam member (600) in an arrangement such that the pin or shaft (100) is drivable reciprocally along a linear path of travel (A) as the eccentric (600) is eccentrically rotatably driven, controllably operating the electrically driven actuator to drive the pin or shaft (100).
 33. A method according to claim 32 wherein a preselected angular position between the angular position that corresponds to the selected maximum moment arm and 70 degrees above defines a fully open valve pin position (PFO) and a preselected angular position between the angular position that corresponds to the selected maximum moment arm and 70 degrees below defines a valve pin position where the gate is closed (PFC). 